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On Theories

‘Theory’ is a word that is often bounded around in the media and politics. It is also very extensively used in the sciences. However, it is here that it often takes on a different meaning to that which the public assume, a meaning that does not accurately convey the scientific process.

Science is comprised of very little fact and very, very many theories, also known as hypotheses. To be frank, any scientist that presents their work as fact should be discredited immediately and hang their head in shame. Each scientifically accepted theory, or hypothesis, is merely the best estimation available to describe or explain the relevant observation(s). It is an idea that has survived the rigours of peer-review and repeated and independent verification to become accepted as the best explanation available to account for the observed results. Even at this point however, it is not fact. Far from it. New information, analysis or technology may in the future, near or distant, prove it wrong despite years, decades or even centuries of obedient acceptance, and a new theory will have to be devised, tested and retested to take its predecessor’s place. This is how science is done, how it progresses and moves forwards. The ephemeral nature of the process, from inception to acceptance, is perhaps what sets science apart from other disciplines. No theory is sacred; they can all be revolutionised in an instant.

This definition extends to include popular and extensively researched hypotheses, such as the theory of evolution by natural selection and Einstein’s theory of relativity – itself a product of revolutionising Newton’s earlier theory of gravitation that had been accepted for over 300 years. These are the best, the most rigorously tested and repeatedly challenged theories to survive the scientific process and become accepted as the nearest available approximation to describe the speciation of living creatures and the physical laws governing the movement of large planetary bodies, respectively. They are great examples of theories that have stood the test of time: evolution by natural selection first being proposed by biologists Charles Darwin and Alfred Russel Wallace in the mid to late 19th century.

As a great example of the misapprehension of the meaning of theory in the scientific sense, evolution as a ‘theory’ is one of the favourite jumping-off points for religious creationists who point to the perceived uncertainty inferred by the word as an effective argument against its ability to accurately describe the fundamental driving force behind biology. “Ah, but it’s only a theory”, they say, “and therefore it is merely your opinion that it is more effective at describing speciation than the Genesis saga of the Old Testament”. This viewpoint illustrates two things. Firstly, a fundamental misunderstanding of the term ‘theory’ as a descriptor of a scientific paradigm, and secondly, a basic understanding of biology.

An example of a testable theory (from the wonderful webcomic xkcd)

Just because it is ‘only’ a theory doesn’t mean it can be completely discredited in one fell-swoop. Extraordinary claims require extraordinary evidence, and paradigm-changing ideas are only very rarely accepted as theory without serious opposition and incredible evidence. Generally, it is a gradual process – improvement, tinkering, refining, acceptance. If creationist ideas had anywhere remotely near as much scientifically verified evidence in support as evolution does, it would have to be accepted by science. The process is not defined by the religious ideas or politics of individual scientists, despite the insistence of certain areas of the media, but rather by whichever theory has the greater corroborating evidence behind it. If it was the case that it was creationism or intelligent design or aliens that were responsible for differentiating all life on Earth, and the evidence was robust, scientists would be in support. But the fact, and this is a fact, is that it simply isn’t.

Awards

Short-listed for the Wellcome Trust Science Writing Prize 2012:
For this article.

Welcome!

Astrobiology and the study of planets throughout the galaxy deal with some of the most profound questions regarding our existence: where did we come from, are there other worlds like ours out there, and are we alone?

I don't profess to be able to answer these questions, but that doesn't stop me from cobbling together some loosely coherent thoughts to share with interested readers. I find it helps me to maintain a cosmic perspective.

I can also be found at the University of East Anglia, where I am completing a PhD in the Centre for Ocean and Atmospheric Science broadly focussed on planetary habitability, astrobiology and global biogeochemical cycling on Earth.

I'm a Science Collaborator at the University of Puerto Rico at Arecibo's excellent Planetary Habitability Laboratory. Visit the PHL website for in-depth habitability assessments and exoplanet visualisation.

I am also a committee member of the Astrobiology Society of Britain. Visit the ASB website for more information about astrobiology in the UK:

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